Improvement in whiffletrees



G. D. MARSH. Whiffletree.

No. 210,463. Patented Dec. 3,1878.

UNITED STATES PATENT @FFIGE.

CALVIN D. MARSH, OF WILLIAMSPORT, PENNSYLVANIA.

I M PROVEMENT IN WH I F FLETRE ES.

Specification forming part of Letters Patent No. 210,463, dated December3, 1878; application filed November 12, 1878. i

To all whom it may concern:

Be it known that I, G. D. MAR-SH, of Williamsport, Lycoming county, inthe State of Pennsylvania, have invented certain new and usefulImprovements relating to Whiffletrees and Eveners, of which thefollowing is a specification:

My improvement is more especially intended for the evencrs of heavywagons; but it may be used with light carriages, and even forwhiffletrces.

I will describe the device as applied to an evener. There are two parts,hinged together at the center, and equipped with a spring, which rendersthe construction flexible or yieldin g. I employ a half-elliptic spring,standing in front of the hinge, and bearing against the properly-facedfront edge of each part. I provide a slotted strap on the upper side,and the same on the under side in rear of the hinge, which prevents theevener from yielding too far. My improvement produces an evener with animportant combination of qualities.

The accompanying drawings form a part of this specification, andrepresent what I consider the best means of carrying out the invention.

Figure 1 is a plan view of my improved whiffletree; and Fig. 2 is thesame with the device partly strained, as in use, and slightly favoringthe backward animal. Fig. 3is a front view of the whiffletree.

Similar letters of reference indicate like parts in the figures.

A A are tapering pieces of hard wood, adapted to abut together fairly attheir larger ends, and to constitute an evener of substantially theusual form and qualities, except as shall further appear. The ends areequipped with any ordinary provisions for attaching the horses to thewhiffletrees.

The front face of each of the parts A A is formed with a metal plate, aa which, near each end, is bent forward or flanged at the top andbottom,to form a guide sufficiently heavy. The half-elliptical spring Dperforms the important function of affording the principaltransverse'strength of the device, and by its yielding makes the actiongentle on the horses, however rough may be the road over which the loadis pulled. The straps a a are united to riveting or otherwise.

form a strong hinged joint, B. I have shown the center-pin of this jointB as extended downward to form a means of joining it to the cross-bar.(Not represented.)

O is a strap, which takes hold of the centerpin of the hinge B above andbelow the parts A A It forms, by means of the gib E, a strong-supportfor the center of the elliptic spring D. I The parts 0 D E may be joined.by The ends of the spring D bear against the fronts of the respectiveparts A A and are maintained reliably in position by the flanges on thefront plates, a (o The wood of the parts A B is sufficiently secured tothe hinge at the center by throughbolts or long rivets.

G G are slotted straps, mounted respectively on the upper and lowerfaces of the parts A A They are pivoted on the part A by a through-boltor rivet, 9. Near the other end of each strap G is a longitudinal slot,{1, in which is received an extended end of another through-bolt orrivet, 9

So long as the evener is subjected to little or no strain it performs inall respects like an ordinary evener; but when the strain exceeds thetension of the spring D, the parts A A turn more orless on the hinge Bat the center in front, and, thus conditioned, the device yields to eachmovement of the team, or to each variation in the resistance. Thetension of the spring D becomes, of course, greater as it is more andmore deflected. In all ordinary conditions the spring will yield witheach variation in the force; but when the force is either momentarily orpermanently very great, and overcomes the tension of the spring D so faras to take up all the motion allowed by the slots 9 in the straps G, thelatter bear on the through-bolt g and the straps Gr become strong ties,to prevent the evener from being any more bent. Thus conditioned, theevener serves again as an ordinary rigid evener; but in the bentconditionit performs the ordinary function of a bent evener to introduce a change in the leverage, and thus to favor the animal which is mostin the rear.

The fact that the strap 0 extends considerably forward of the hinge B,and that the spring D is bent as shown, allows a considerable fiexure ofthe evener before the spring becomes straight, and still more before itbecomes bent in the opposite direction. The friction of the leaves ofthe half elliptic springs and the considerable friction of the ends ofthe springs on the front plates, a a is of advantage in determining theelastic action. It is analogous to the effect of friction in ellipticbearing-springs in carriages. It yields to all irregularities andsoftens concussion, but without engenderin g a perpetual vibration,which would be annoying. It makes what may be called a dead elasticity.

The straps Gr prevent the springs D from being overstrained under anyconditions. They are favorably situated for receiving any excess offorce.

Modifications may be made. The hinge B may be formed independently, orit may be formed in one with the plates a a Still further, the plates aa may be extended angularly across the body of the parts A A and evencaused to take hold more or less on the back faces of the respectivewood parts. Instead of slotting only one end of each plate G, both endsmay be slotted and allowed to play loosely on their bolts or holdfasts g9 A single slot may be made to extend the whole distance; or, instead ofplates, a sufficient link,

7 analogous to the link of a chain, may be employed. The gib E may bedispensed with, and the spring allowed to bear directly against theinner face of its inclosing-strap. Any ordinary or suitable means may beemployed by indenting the leaves of the spring into each other, orotherwise, to hold them reliably in their proper relations to each otherto allow the required motion.

Vhiffletrees of the same character, or ordinary whiffletrees, may beattached in any suitable manner.

My invention relieves the jar on the shoulders of the horses, and also011 the wagon. 1t interposes an efiicient stop to prevent the springbeing overstrained, while leaving the evener free to turn and performall its functions other than yielding. All the parts are readilyaccessible for inspection and repairs.

The stop-ties G may be dispensed with, or the function maybe partiallysupplied by other means, as by an extension of the gib E, so as to forma rigid bearing to bear against the front face of the spring D, when itis in danger of being too much deflected.

I claim as my invention- 1. The improved whiffletree described, havingthe parts A A connected by the flexible hinge B, in combination with thestrap 0 and extended spring D, arranged for joint operation as and forthe purposes herein specified.

2. The stop-ties G, in combination with the hinged parts A A andextended front spring, D, as herein specified.

3. The compound whiffletree described, having the two parts A A hinge B,strap 0, half-elliptic spring D, gib E, and stop-ties G, with theirholding means g 9 combined and arranged as and for the purposes hereinspecified.

In testimony whereof I have hereunto set my hand this 5th day ofNovember, 1878, in the presence of two subscribing witnesses.

CALVIN D. MARSH.

Witnesses PHILIP MILLER, WILLIAM McCoy.

